Wyeth may have known as early as the 1970Ã¢â‚¬â„¢s that its hormone replacement drug, which later became Prempro, was associated with a high rate of breast cancer. According to recent published reports, Wyeth researchers saw cancer risks associated with hormone-replacement drugs as early as 1976. These concerns were brought to the attention of Wyeth executives several years later in the form of an internal memo. This memo alerted Wyeth executives that the FDAÃ¢â‚¬â„¢s request for more extensive safety testing of Prempro could publicly reveal the drugs link to breast cancer.
The memo was entered as evidence in the trial of an Arkansas woman who is suing Wyeth after being diagnosed with breast cancer after using the companyÃ¢â‚¬â„¢s hormone replacement drugs. There are currently over 5000 lawsuits pending against Wyeth claiming that Premarin and Prempro are linked to breast cancer. Wyeth denies that the menopausal drugs cause breast cancer and claim they have conducted many studies to prove this. Premarin contains estrogen and Prempro combines that estrogen with progestin.

Dr. John Gueriguian, a former FDA official told jurors that, Ã¢â‚¬Å“It’s not appropriate for a drug firm to choose not to do a study because it might be embarrassing.Ã¢â‚¬Â Dr. Gueriguian has extensive experience with the drug approval process. He was strongly opposed the approval of Rezulin, a Pfizer diabetes drug, in the 1990Ã¢â‚¬â„¢s. It is speculated that his objections to Rezulin led to his dismissal from the drugÃ¢â‚¬â„¢s review team.

Despite Dr. GueriguianÃ¢â‚¬â„¢s protests Rezulin was approved, but the side effects he was concerned about became a reality. In March 2000 Pfizer pulled Rezulin off the U.S. market after researchers linked the drug to at least 63 liver-related deaths.

Approximately 6 million women took Premarin and Prempro to treat menopause symptoms such as hot flashes and mood swings. The drugs generated concern in 2002 when a government-sponsored study linked them to higher cancer risks. The study, backed by the U.S. National Institutes of Health and conducted by the Women’s Health Initiative, concluded that women who received a combination of estrogen and progestin had a 24 percent higher risk of invasive breast cancer.